Surgical cutting instrument that analyzes tissue thickness

ABSTRACT

A surgical instrument with a tissue-clamping end effector, where actuation of the instrument is locked out when the thickness of the tissue clamped in the end effector is not within a specified thickness range. The end effector may comprise a tissue thickness module that senses the thickness of the tissue clamped in the end effector. The surgical instrument also comprises a control circuit in communication with the tissue thickness module. The control circuit prevents actuation of a working portion of the end effector when the thickness of the tissue clamped in the end effector is not within the specified thickness range.

PRIORITY CLAIM

The present application is a continuation application claiming priorityunder 35 U.S.C. §120 to U.S. patent application Ser. No. 12/647,134,entitled SURGICAL CUTTING INSTRUMENT THAT ANALYZES TISSUE THICKNESS,filed Dec. 24, 2009, now U.S. Pat. No. 8,851,354, which is incorporatedherein by reference in its entirety.

BACKGROUND

Surgical staplers are used to simultaneously make a longitudinalincision in tissue and apply lines of staples on opposing sides of theincision. Such instruments commonly include an end effector having apair of cooperating jaw members that, if the instrument is intended forendoscopic or laparoscopic applications, are capable of passing througha cannula passageway. One of the jaw members receives a staple cartridgehaving at least two laterally spaced rows of staples—one on each side ofthe knife channel. The other jaw member defines an anvil havingstaple-forming pockets aligned with the rows of staples in thecartridge. The instrument includes a plurality of reciprocating wedgesthat, when driven distally, pass through openings in the staplecartridge and engage drivers supporting the staples to effect the firingof the staples toward the anvil. Simultaneously, a cutting instrument(or knife) is drawn distally along the jaw member so that the clampedtissue is cut and fastened (e.g., stapled) at the same time.

An example of a surgical stapler suitable for endoscopic applications isdescribed in published U.S. Patent Application Publication No.2004/0232196 A1, entitled, SURGICAL STAPLING INSTRUMENT HAVING SEPARATEDISTINCT CLOSING AND FIRING SYSTEMS, now U.S. Pat. No. 7,000,818, thedisclosure of which is herein incorporated by reference in its entirety.In use, a clinician is able to close the jaw members of the stapler upontissue to position the tissue prior to firing. Once the clinician hasdetermined that the jaw members are properly gripping tissue, theclinician can then fire the surgical stapler, thereby severing andstapling the tissue. The simultaneous severing and stapling actionsavoid complications that may arise when performing such actionssequentially with different surgical tools that respectively only severor staple.

Motor-driven endocutters are known in the art. In such devices, anelectric motor powers the cutting and fastening action of theinstrument. It is also known to use an on-board battery, located in thehandle of the instrument, to power the motor. Published U.S. PatentApplication Publication No. 2007/0175952 A1, entitled MOTOR-DRIVENSURGICAL CUTTING AND FASTENING INSTRUMENT WITH LOADING FORCE FEEDBACK,now U.S. Pat. No. 7,416,101, the disclosure of which is hereinincorporated by reference in its entirety, describes one suchmotor-driven surgical instrument.

SUMMARY

In one general aspect, the present invention is directed to a surgicalinstrument with a tissue-clamping end effector, where actuation of theinstrument is locked out when the thickness of the tissue clamped in theend effector is not within a specified thickness range. According tovarious embodiments, the end effector comprises a tissue thicknessmodule that senses the thickness of the tissue clamped in the endeffector. The surgical instrument also comprises a control circuit incommunication (e.g., wireless communication) with the tissue thicknessmodule. The control circuit prevents actuation of a working portion ofthe end effector when the thickness of the tissue clamped in the endeffector is not within the specified thickness range. In that way,actuation of the instrument can be locked out when too much or toolittle tissue is clamped in the end effector. This prevents theinstrument from firing in situations where it should not be fired.

According to various implementations, the end effector comprises: firstand second opposing jaw members; and a disposable cartridge (such as adisposable staple cartridge) located in the first jaw member. The tissuethickness module may be part of the disposable cartridge, and maycomprise a Hall effect sensor. The second jaw member may comprise amagnet, where the Hall effect sensor senses a magnetic field strengthfrom the magnet that is indicative of the thickness of the tissueclamped in the end effector. The tissue thickness module communicatesdata to the control circuit, the data comprising: (i) data indicative ofthe thickness of the tissue clamped in the end effector; and (ii) dataindicative of a cartridge type of the disposable cartridge. The controlcircuit may comprise a processing unit programmed to determine whetherthe tissue clamped in the end effector is within the specified thicknessrange for the disposable cartridge based on the data communicated to thecontrol circuit by the tissue thickness module. In that connection, thecontrol circuit may comprise solid state memory that stores thicknessrange data for one or more cartridge types. The processing unit may beprogrammed to determine whether the tissue clamped in the end effectoris within the specified thickness range for the disposable cartridgebased on the data communicated to the control circuit by the tissuethickness module by comparing the data indicative of the thickness ofthe tissue clamped in the end effector to stored thickness range datafor the cartridge type of the disposable cartridge in the end effector.

FIGURES

Various embodiments of the present invention are described herein by wayof example in connection with the following figures, wherein:

FIGS. 1-2 and 12 are views of a surgical instrument according to variousembodiments of the present invention;

FIGS. 3-5 are exploded views of the end effector and shaft of a surgicalinstrument according to various embodiments of the present invention;

FIGS. 6-7 are views of the end effector according to various embodimentsof the present invention;

FIG. 8 is a block diagram of a tissue thickness module according tovarious embodiments of the present invention;

FIG. 9 is a block diagram of a motor control circuit according tovarious embodiments of the present invention;

FIG. 10 is a block diagram of a radio module according to variousembodiments of the present invention; and

FIG. 11 is flow chart of a process executed by the motor control circuitaccording to various embodiments of the present invention.

DESCRIPTION

Certain embodiments of the present invention will now be described toprovide an overall understanding of the principles of the structure,function, manufacture, and use of the devices and methods disclosedherein. One or more examples of these embodiments are illustrated in theaccompanying drawings. Those of ordinary skill in the art willunderstand that the devices and methods specifically described hereinand illustrated in the accompanying drawings are non-limitingembodiments and that the scope of these embodiments is defined solely bythe claims. The features illustrated or described in connection with oneembodiment may be combined with the features of other embodiments. Suchmodifications and variations are intended to be included within thescope of the appended claims.

In general, embodiments of the present invention are directed to asurgical instrument that prevents firing of the instrument if thethickness of the tissue clamped in the end effector of the instrument isoutside of acceptable limits (e.g., too thick or too thin). That way,the instrument can be prevented from firing in situations when it shouldnot be fired. If the tissue thickness is not within the acceptablelimits for the instrument, the operator (e.g., clinician) can adjust thetissue thickness or change the cartridge, for example.

The instrument may be a motor-drive instrument or a hand-poweredinstrument, according to various embodiments. FIGS. 1 and 2 depict amotor-driven surgical cutting and fastening instrument 10 according tovarious embodiments of the present invention. The illustrated embodimentis a linear endoscopic instrument and, in general, the embodiments ofthe instrument 10 described herein are linear endoscopic surgicalcutting and fastening instruments. It should be noted, however, that theinvention is not so limited and that according to other embodiments ofthe present invention, the instrument may be another type of endoscopicinstrument, such as a circular or curved endocutter. In addition, theinstrument may be a non-endoscopic surgical cutting and fasteninginstrument, such as a laparoscopic or open instrument.

The surgical instrument 10 depicted in FIGS. 1 and 2 comprises a handle6, a shaft 8, and an end effector 12 connected to the shaft 8. Invarious embodiments, the end effector 12 can be articulated about anarticulation pivot 14. An articulation control 16 may be providedadjacent to the handle 6 to effect rotation of the end effector 12 aboutthe articulation pivot 14. In the illustrated embodiment, the endeffector 12 is configured to act as an endocutter for clamping, severingand stapling tissue, although, in other embodiments, different types ofend effectors may be used, such as end effectors for other types ofsurgical devices, such as graspers, cutters, staplers, clip appliers,access devices, drug/gene therapy devices, ultrasound, RF or laserdevices, etc. More details regarding RF devices may be found in U.S.Pat. No. 5,403,312 and U.S. patent application Ser. No. 12/031,573,entitled SURGICAL CUTTING AND FASTENING INSTRUMENT HAVING RF ELECTRODES,filed Feb. 14, 2008, both of which are incorporated by reference intheir entirety.

The handle 6 of the instrument 10 may include a closure trigger 18 and afiring trigger 20 for actuating the end effector 12. It will beappreciated that instruments having end effectors directed to differentsurgical tasks may have different numbers or types of triggers or othersuitable controls for operating the end effector 12. The end effector 12is shown separated from the handle 6 by the elongate shaft 8. In oneembodiment, a clinician or operator of the instrument 10 may articulatethe end effector 12 relative to the shaft 8 by utilizing thearticulation control 16, as described in more detail in published U.S.Patent Application Publication No. 2007/0158385 A1, entitled SURGICALINSTRUMENT HAVING AN ARTICULATING END EFFECTOR, now U.S. Pat. No.7,670,334, which is incorporated herein by reference in its entirety.

The end effector 12 includes in this example, among other things, astaple channel 22 and a pivotally translatable clamping member, such asan anvil 24, which are maintained at a spacing that assures, when theanvil 24 is in its clamped position, effective stapling and severing oftissue clamped in the end effector 12. The handle 6 includes adownwardly extending pistol grip 26, towards which a closure trigger 18is pivotally drawn by the clinician to cause clamping or closing of theanvil 24 toward the staple channel 22 of the end effector 12 to therebyclamp tissue positioned between the anvil 24 and channel 22. The firingtrigger 20 is farther outboard of the closure trigger 18. Once theclosure trigger 18 is locked in the closure position, the firing trigger20 may rotate slightly toward the pistol grip 26 so that it can bereached by the operator using one hand. Then the operator may pivotallydraw the firing trigger 20 toward the pistol grip 12 to cause thestapling and severing of clamped tissue in the end effector 12. In otherembodiments, different types of clamping members besides the anvil 24could be used. The handle 6 may also include an upper portion 28 thatmay sit on top of the user's hand when the user grips the pistol gripportion 26 with his/her hand.

It will be appreciated that the terms “proximal” and “distal” are usedherein with reference to a clinician gripping the handle 6 of aninstrument 10. Thus, the end effector 12 is distal with respect to themore proximal handle 6. It will be further appreciated that, forconvenience and clarity, spatial terms such as “vertical” and“horizontal” are used herein with respect to the drawings. However,surgical instruments are used in many orientations and positions, andthese terms are not intended to be limiting and absolute.

In operational use, the closure trigger 18 may be actuated first. Oncethe clinician is satisfied with the positioning of the end effector 12,the clinician may draw back the closure trigger 18 to its fully closed,locked position proximate to the pistol grip 26. Drawing back of theclosure trigger 18 causes the anvil 24 to rotate downwardly, clampingthe tissue between the anvil 24 and channel 27. The firing trigger 20may then be actuated. Actuation of the firing trigger 20 causes thecutting instrument in the end effector 12 to sever the clamped tissue,and causes the fasteners in the end effector to fasten the severedtissue. The firing trigger 20 returns to the open position (shown inFIGS. 1 and 2) when the clinician removes pressure. A release button 19on the handle 6, when depressed may release the locked closure trigger18. The release button 19 may be implemented in various forms such as,for example, as disclosed in published U.S. Patent ApplicationPublication No. 2007/0175955, entitled SURGICAL CUTTING AND FASTENINGINSTRUMENT WITH CLOSURE TRIGGER LOCKING MECHANISM, which is incorporatedherein by reference in its entirety.

The end effector 12 may include a cutting instrument, such as knife, forcutting tissue clamped in the end effector 12 when the firing trigger 20is retracted by a user. The end effector 12 may also comprise means forfastening the tissue severed by the cutting instrument, such as staples,RF electrodes, adhesives, etc. More details regarding possibleconfigurations of the end effector 12 may be found in the followingpatents and published patent applications, which are incorporated hereinby reference in their entirety: U.S. Pat. No. 5,709,680; U.S. Pat. No.5,688,270; U.S. Pat. No. 7,000,818; U.S. Patent Application PublicationNo. 2005/0173490 A1, now U.S. Pat. No. 7,140,528; U.S. PatentApplication Publication No. 2006/0025809 A1, now U.S. Pat. No.7,506,790; U.S. Patent Application Publication No. 2007/0102453 A1, nowU.S. Pat. No. 7,673,783; U.S. Patent Application Publication No.2007/0102452 A1, now U.S. Pat. No. 7,607,557; U.S. Patent ApplicationPublication No. 2009/0206134 A1, now U.S. Pat. No. 7,857,185; and U.S.Patent Application Publication No. 2009/0206124 A1, now U.S. Pat. No.7,819,298.

The instrument 10 may also comprise a closure system for closing (orclamping) the end effector upon closure (or retraction) of the closuretrigger 18. More details regarding embodiments of an exemplary closuresystem for closing (or clamping) the anvil 24 of the end effector 12 byretracting the closure trigger 18 are provided in the following U.S.patent references, which are incorporated herein by reference in theirentirety: U.S. Patent Application Publication No. 2004/0232196 A1, nowU.S. Pat. No. 7,000,818; U.S. Patent Application Publication No.2007/0175956 A1, now U.S. Pat. No. 7,644,848; U.S. Patent ApplicationPublication. No. 2007/0158385 A1, now U.S. Pat. No. 7,670,334; U.S.Patent Application Publication No. 2007/0175962 A1, now U.S. Pat. No.7,422,139; U.S. Pat. No. 7,464,849; and the references cited in theparagraph above.

A longitudinally movable or rotatable drive shaft located within theshaft 8 of the instrument 10 may drive/actuate the cutting instrumentand the fastening means in the end effector 12. An electric motor,located in the pistol grip portion 26 of the handle 6 of the instrument10, may be used to drive, directly or indirectly (via a gear drivetrain), the drive shaft. In various embodiments, the motor may be a DCbrushed driving motor having a maximum rotation of, approximately,25,000 RPM. In other embodiments, the motor may include a brushlessmotor, a cordless motor, a synchronous motor, a stepper motor, or anyother suitable electric motor. A battery (or “power source” or “powerpack”), such as a Li ion battery, may be provided in the pistol gripportion 26 of the handle 6 adjacent to the motor. The battery supplieselectric power to the motor via a motor control circuit. According tovarious embodiments, a number of battery cells connected in series maybe used as the power source to power the motor. In addition, the powersource may be replaceable and/or rechargeable.

As described in more detail below, operation of the motor may becontrolled by a processor or microcontroller-based control circuit,which may be located in the handle 6 of the instrument 10, near themotor and battery pack. The control circuit may receive input from theend effector 12 relating to the thickness of the tissue clamped betweenthe opposing jaws (e.g., the staple channel 22 and the anvil 24) of theend effector 12. The control circuit may be in communication with thetissue thickness sensing module of the end effector 12 wirelessly or viaa wired connection. If the control circuit determines that the clampedtissue is not within acceptable limits (e.g., too thick or too thin)based on the input from the tissue thickness sensing module, the controlcircuit may lockout operation of the motor, thereby preventing operationof the instrument. Before describing the control circuit, a descriptionof the end effector 12 and the tissue thickness sensing module isprovided.

FIG. 3 is a diagram of the end effector 12 according to variousembodiments of the present invention. As shown in the illustratedembodiment, the end effector 12 may include, in addition to thepreviously mentioned channel 22 and anvil 24, a cutting instrument 32, asled 33, a staple cartridge 34 that is removably seated in the channel22, and a helical screw shaft 36. The cutting instrument 32 may be, forexample, a knife. The anvil 24 may be pivotably opened and closed atpivot pins 25 connected to the proximate end of the channel 22. Theanvil 24 may also include a tab 27 at its proximate end that is insertedinto a component of the mechanical closure system to open and close theanvil 24. When the closure trigger 18 is actuated, that is, drawn in bya user of the instrument 10, the anvil 24 may pivot about the pivot pins25 into the clamped or closed position, thereby clamping tissue betweenthe channel 22 and the anvil 24. If clamping of the end effector 12 issatisfactory, the operator may actuate the firing trigger 20, whichcauses the knife 32 and sled 33 to travel longitudinally along thechannel 22, thereby cutting the tissue clamped within the end effector12. The movement of the sled 33 along the channel 22 causes the staples(not shown) of the staple cartridge 34 to be driven through the severedtissue and against the closed anvil 24, which turns the staples tofasten the severed tissue. In various embodiments, the sled 33 may be anintegral component of the cartridge 34. U.S. Pat. No. 6,978,921,entitled SURGICAL STAPLING INSTRUMENT INCORPORATING AN E-BEAM FIRINGMECHANISM, which is incorporated herein by reference in its entirety,provides more details about such two-stroke cutting and fasteninginstruments. The sled 33 may be part of the cartridge 34, such that whenthe knife 32 retracts following the cutting operation, the sled 33 doesnot retract.

FIGS. 4-5 are exploded views and FIG. 6 is a side view of the endeffector 12 and shaft 8 according to various, non-limiting embodiments.As shown in the illustrated embodiment, the shaft 8 may include aproximate closure tube 40 and a distal closure tube 42 pivotably linkedby a pivot links 44. The distal closure tube 42 includes an opening 45into which the tab 27 on the anvil 24 is inserted in order to open andclose the anvil 24, as further described below. Disposed inside theclosure tubes 40, 42 may be a proximate spine tube 46. Disposed insidethe proximate spine tube 46 may be a main rotational (or proximate)drive shaft 48 that communicates with a secondary (or distal) driveshaft 50 via a bevel gear assembly 52. The secondary drive shaft 50 isconnected to a drive gear 54 that engages a proximate drive gear 56 ofthe helical screw shaft 36. The vertical bevel gear 52 b may sit andpivot in an opening 57 in the distal end of the proximate spine tube 46.A distal spine tube 58 may be used to enclose the secondary drive shaft50 and the drive gears 54, 56. Collectively, the main drive shaft 48,the secondary drive shaft 50, and the articulation assembly (e.g., thebevel gear assembly 52 a-c) are sometimes referred to herein as the“main drive shaft assembly.”

A bearing 38, positioned at a distal end of the staple channel 22,receives the helical drive screw 36, allowing the helical drive screw 36to freely rotate with respect to the channel 22. The helical screw shaft36 may interface a threaded opening (not shown) of the knife 32 suchthat rotation of the shaft 36 causes the knife 32 to translate distallyor proximately (depending on the direction of the rotation) through thestaple channel 22. Accordingly, when the main drive shaft 48 is causedto rotate by actuation of the firing trigger 20, the bevel gear assembly52 a-c causes the secondary drive shaft 50 to rotate, which in turn,because of the engagement of the drive gears 54, 56, causes the helicalscrew shaft 36 to rotate, which causes the knife driving member 32 totravel longitudinally along the channel 22 to cut any tissue clampedwithin the end effector. The sled 33 may be made of, for example,plastic, and may have a sloped distal surface. As the sled 33 traversesthe channel 22, the sloped forward surface may push up or drive thestaples in the staple cartridge through the clamped tissue and againstthe anvil 24. The anvil 24 turns the staples, thereby stapling thesevered tissue. When the knife 32 is retracted, the knife 32 and sled 33may become disengaged, thereby leaving the sled 33 at the distal end ofthe channel 22.

In the illustrated embodiment, the end effector uses a rotatable,helical screw shaft 36 to drive the cutting instrument 32. Such ahelical drive screw may be used in embodiments where a rotating drivemember is used. In other embodiments, a longitudinally reciprocatingdrive member may be used to power the cutting instrument. The endeffector 12 may be modified accordingly to suit such a longitudinallyreciprocating drive member. More details regarding such end effectorsmay be found in U.S. Pat. No. 7,140,528 and U.S. Pat. No. 7,000,819,which are incorporated herein by reference in their entirety.

According to various embodiments, the replaceable staple cartridge 34may comprise a tissue thickness sensing module that senses the thicknessof tissue clamped in the end effector 12 between the staple channel 22(including the staple cartridge 34) and the anvil 24. According tovarious, non-limiting embodiments, as shown in FIG. 7, the tissuethickness sensing module 60 may be located at a distal end 62 of thestaple cartridge 34, such that it is out of the way of the staples ofthe staple cartridge 34 when the staples are fired. FIG. 8 is a blockdiagram of the tissue thickness sensing module 60 according to variousembodiments. As shown in FIG. 8, the tissue thickness sensing module 60may comprise a tissue thickness sensor 64, a controller 65, a radiomodule 70, and a power source 74. The controller 65 may comprise aprocessor unit (CPU) 66 and a memory unit 68. In various embodiments,the tissue thickness sensor 64 may comprise a Hall effect sensor thatdetects the thickness of the tissue clamped in the end effector 12 basedon the magnetic field from a magnet 78 located, for example, at a distalend 80 of the anvil 24, as shown in FIG. 7. When the clinician closesthe anvil 24 by retracting the closure trigger 18, the magnet 78 rotatesdownwardly closer to the sensor 64, thereby varying the magnetic fielddetected by the sensor 64 as the anvil 24 rotates into the closed (orclamped position). The strength of the magnetic field from the magnet 78and sensed by the sensor 64 is indicative of the distance between thechannel 22 and the anvil 24, which is indicative of the thickness of thetissue clamped between the channel 22 and the anvil 24 when the endeffector 12 is in the closed (or clamped) position.

The memory unit 68 of the controller 65 may comprise one or more solidstate read only memory (ROM) and/or random access memory (RAM) units. Invarious embodiments, the CPU 66 and the memory unit(s) 68 may beintegrated into a single integrated circuit (IC), or multiple ICs. TheROM memory unit(s) may comprise flash memory. The ROM memory unit(s) maystore code instructions to be executed by the CPU 66 of the controller65. In addition, the ROM memory unit(s) may store data indicative of thecartridge type of the cartridge 34. That is, for example, ROM memoryunit(s) 68 may store data indicating the model type of staple cartridge34. As explained further below, the motor control circuit in the handle6 of the instrument 10 may utilize the tissue thickness information andthe model type of the staple cartridge 34 to determine if the tissueclamped in the end effector 12 is too thick or too thin, based on thespecified tissue thickness range for the particular staple cartridge 34.The radio module 70 may be a low-power, 2-way radio module thatcommunicates wirelessly, using a wireless data communication protocol,with the motor control circuit in the handle 6 of the instrument 10.According to various embodiments, the radio module 70 may communicatewith the motor control circuit using a communication frequency that issuitable for transmission through human tissue. The communicationsbetween the radio module 70 and the motor control circuit may use theMICS (Medial Implant Communication Service) frequency band (402-405MHz), a suitable industrial, scientific and medical (ISM) radio band(such as 433 MHz center frequency or 915 MHz center frequency), or anyother suitable, human-tissue-permeable frequency band. The power source74 may comprise a suitable battery cell for powering the components ofthe tissue thickness sensing module 60, such as a Lithium-ion battery orsome other suitable battery cell.

FIG. 9 is a diagram of the motor control circuit 100 according tovarious, non-limiting embodiments. The motor control circuit 100 may belocated in the handle 6 of the instrument 10, in close proximity withthe motor 104 and battery pack 106, and spaced away from the tissuethickness sensing module 60 in the end effector 12 by the shaft 8, forexample. As such, the motor control circuit 100 may wirelesslycommunicate with the tissue thickness sensing module 60 as describedherein, although in other embodiments, there may be a wired connection,with wires running through the shaft 8 between the motor control circuit100 and the tissue thickness sensing module 60 to handle thecommunications therebetween.

As shown in FIG. 9, the motor control circuit 100 may comprise,according to various embodiments, a power switching circuit 101, acontroller 108, and a radio module 110. The radio module 110 maycommunicate with the radio module 70 of the tissue thickness sensingmodule 60. Therefore, the radio module 100 may be a low, power modulethat operates at the same frequency as the radio module 70 and uses thesame communication protocol. The radio modules 70, 100, as shown in FIG.10, may both comprise, according to various embodiments, transmit andreceive antennas 200, 202, an antenna switch 204, a transmit/receiveswitch 206, RF modulator/demodulator 208, a coder/decoder (codec) 210,and a baseband processor 212. The antennas 200, 2002 of the motorcontrol circuit 100 and the tissue thickness sensing module 60 may bemicrostrip antennas, for example.

The power switching circuit 101 may comprise, according to variousembodiments, a power switch 103 and a forward/reverse switch 102, thatcollectively connect the motor 104 and the battery pack 106 in order toconnect power from the battery pack 106 to the motor 104. In variousembodiments, the forward/reverse switch 102 may comprise adouble-pole/double throw relay that, depending on its polarity,determines whether the motor 104 forward rotates or reverse rotates. Thecontroller 108 may control the operation of the switches 102-103. Invarious embodiments, the controller 108 may be implemented as amicrocontroller that comprises a processing unit (CPU) 114 and memory116. The memory 116 may comprise solid state ROM and/or RAM memoryunits. The ROM memory unit(s) may comprise instruction code that isexecuted by the processing unit 114. The processing unit 114 and thememory 116 may be integrated into a single IC, or multiple ICs may beused. The controller 108 and radio module 112 of the motor controlcircuit 100 may be powered by the battery pack 106.

As shown in FIG. 9, the controller 108 may receive a number of inputsand, based on processing of those inputs, may control the switches102-103, to thereby appropriately control the motor 104 of theinstrument 10. The inputs to the controller 108 may include a fire input120, a cutting instrument position input 122, and any other suitableinputs. The fire input 120 may indicate the status of the firing trigger20, such as whether the clinician has retracted the firing trigger 20 tocommence a cutting stroke by the knife in the end effector 12 andwhether the clinician has let go of the firing trigger 20 to end thecutting stroke. The fire input 120 may be from a sensor, such as aproportional switch, responsive to the firing trigger 20. The cuttinginstrument position input 122 may indicate the position of the cuttinginstrument 34 in the end effector 12 in the course of the cuttingstroke. The controller 108 may use this input to determine the positionof cutting instrument 34 in the cutting stroke, such as whether thecutting instrument 34 is near or at the end of the cutting stroke. Asthe cutting instrument 34 approaches the end of the cutting stroke, thecontroller 108 may reduce the rotation rate of the motor 104, and mayreverse the rotation of the motor 104 when the cutting instrument 34reaches the end of the cutting stroke. The controller 108 may alsoreduce the rate of rotation of the motor 104 when the cutting instrumentis close to its initial, home position at the proximate end of the endeffector 12 when the cutting instrument is retracted, and may stop themotor 104 when the cutting instrument is fully retracted. More detailsregarding a proportional firing trigger switch are provided in thefollowing U.S. patent references, which are incorporated herein byreference in their entirety: U.S. Patent Application Publication No.2007/0175957, now U.S. Pat. No. 7,770,775; U.S. Patent ApplicationPublication No. 2007/0175958, now U.S. Pat. No. 7,766,210; and U.S.Patent Application Publication No. 2007/0175959, now U.S. Pat. No.7,568,603. More details regarding instruments with cutting instrumentposition sensors are provided in the following U.S. patent references,which are incorporated herein by reference in their entirety: U.S.patent application Ser. No. 12/235,782, now U.S. Pat. No. 8,210,411; andU.S. patent application Ser. No. 12/235,972, now U.S. Patent ApplicationPublication No. 2010/0076475.

Of course, the controller 108 also receives input data from the tissuethickness sensing module 60 via the radio module 110. The input datafrom the tissue thickness sensing module 60 may include: (i) the tissuethickness data as sensed by the sensor 64 of the tissue thicknesssensing module 60; and (ii) the cartridge model data indicative of themodel type of the staple cartridge 34, which is stored in the memory 68of the tissue thickness sensing module 60. Based on this data, thecontroller 108 of the motor control circuit 100 may determine whetherthe tissue clamped in the end effector 12 is within the specified rangefor the specific staple cartridge 34. If the tissue thickness is withinthe specified range, the controller 108 may control the switches 102-103such that power is connected to the motor 104 (assuming other input datais appropriate). On the other hand, if the tissue thickness is notwithin the specified range, the controller 108 may control the switch103 such that power is not connected to the motor 104, thereby lockingout the motor 104 based on the tissue thickness and preventing operationof the instrument 10.

FIG. 11 is a flowchart of a process executed by the controller 108according to various embodiments. The process may be executed by theprocessing unit 114 by executing code stored in the memory 116. Theprocess may start at step 150, where the controller 108 determineswhether the thickness of the tissue clamped in the end effector 12 iswithin the specified range for the particular staple cartridge 34. Thecontroller 108 may determine this by comparing the tissue thickness datafrom the sensor 64 to the specified range for the particular staplecartridge 34. The controller 108 may determine the specified thicknessrange for the staple cartridge using (i) the staple cartridge model datatransmitted from the tissue thickness sensing module 60 and (ii) alook-up table (or other data storage structure) in the memory 116 of thecontroller, which table stores data indicating the specified thicknessrange for a number of staple cartridge model types. The specifiedthickness range may include a minimum thickness and a maximum thicknessfor each model type. For example, different cartridge model types mayhave different length staples. Longer staples may be able to accommodatemore tissue in the end effector than cartridges with shorter staplelengths. As such, the upper thickness limit may be greater forcartridges with longer staples, and the lower thickness limit may belower for cartridges with shorter staple lengths. If the clamped tissuethickness is less than the minimum thickness or greater than the maximumthickness for the model type of the cartridge 34, the tissue thicknessis outside of the specified range.

If the tissue thickness is outside of the specified thickness range forthe staple cartridge 34, the process advances to step 152, where thecontroller 108 controls the power switch 103 such that power switch 103is in an open, non-conducting state, so that power from the battery pack106 is not coupled to the motor 104. As such, the motor 104 does notreceive power and is locked out of operation, thereby preventingactuation of the end effector 12. On the other hand, if the tissuethickness is within the specified thickness range for the staplecartridge 34, the process advances to step 154, where the controller 108determines whether the firing trigger 20 is retracted based on the fireinput 120. If it is not, the process advances to step 152 so that powerfrom the battery pack 106 is not coupled to the motor 104. If, on theother hand, the firing trigger 20 is retracted, the process advances tostep 156, where the controller 108 determines the position of thecutting instrument 34 in the cutting stroke based on the cuttinginstrument position input 22. If the position of the cutting instrumentis in the forward stroke, the process advances to step 158, where thecontroller 108 outputs a control signal to the forward/reverse switch102 to cause the forward/reverse switch 102 to be in a state thatcouples power to the motor 104 such that the motor 104 forward rotates.Conversely, if the position of the cutting instrument in the cuttingstroke requires reverse rotation of the motor 104, the process advancesto step 160, where the controller 108 outputs a control signal to theforward/reverse switch 102 to cause the forward/reverse switch 102 to bein a state that couples power to the motor 104 such that the motor 104reverse rotates. The process may run in an ongoing manner throughout asurgical procedure involving the instrument 10. That way, if for somereason the tissue thickness goes out of range during the procedure, thecontroller 108 can take appropriate action in response to the real-timetissue thickness data received from the tissue thickness module 60.

Returning to FIG. 9, the controller 108 may also receive feedback fromthe motor 104 regarding conditions of the motor 104, such as rate ofrotation, rotation direction, etc. The controller 108 may use the datain controlling the motor 104. Also, the controller 108 may outputcontrol signals to one or more output devices 124. The output devices124 may comprise visual indicators, such as illuminators (e.g., lightemitting diodes), and/or audible indicators, such as speakers. Forexample, the output devices 124 may comprise a number of LEDs located onthe outside of the handle 6 of the instrument and visible to theoperator of the instrument 10 when the instrument 10 is in use. One LEDmay be turned on when the clamped tissue thickness is in the specifiedthickness range for the staple cartridge; a second LED may be turned onwhen the clamped tissue thickness is outside the specified thicknessrange for the staple cartridge; a third LED may be turned on when themotor 104 is forward rotating; a fourth LED may be turned on when themotor 104 is reverse rotating; etc.

In addition, in other embodiments, the transmissions from the tissuethickness module 60 may be received by a receiver other than the motorcontrol circuit 100. For example, with reference to FIG. 12, thetransmissions from the tissue thickness module 60 may be received by avisual display unit 160 and/or a computer system 170. The visual displayunit 160 may comprise a RF radio module 162 for communicating with thetissue thickness module 60. Images based on data from the tissuethickness module 60 may be displayed on the display 160. That way, theclinician may see real-time data regarding the thickness of the clampedtissue throughout a procedure involving the instrument 10. The visualdisplay unit 160 may comprise a monitor, such as a CRT monitor, a plasmamonitor, a LCD monitor, or any other suitable visual display monitor.Similarly, the computer system 170 may comprise a RF radio module 172for communicating with the tissue thickness module 60. The computersystem 170 may store the data from the tissue thickness module 60 in amemory unit (e.g., a ROM or hard disk drive) and may process the datawith a processor.

The surgical instruments disclosed herein can be designed to be disposedof after a single use, or they can be designed to be used multipletimes. In either case, however, the device can be reconditioned forreuse after at least one use. Reconditioning can include any combinationof the steps of disassembly of the surgical instrument, followed bycleaning or replacement of particular pieces, and subsequent reassembly.In particular, the surgical instrument can be disassembled, and anynumber of the particular pieces or parts of the device can beselectively replaced or removed in any combination. Upon cleaning and/orreplacement of particular parts, the surgical instrument can bereassembled for subsequent use either at a reconditioning facility, orby a surgical team immediately prior to a surgical procedure. Thoseskilled in the art will appreciate that reconditioning of a surgicalinstrument can utilize a variety of techniques for disassembly,cleaning/replacement, and reassembly. Use of such techniques, and theresulting reconditioned surgical instrument, are all within the scope ofthe present application.

Preferably, the surgical instrument described herein will be processedbefore surgery. First, a new or used instrument is obtained and ifnecessary cleaned. The instrument can then be sterilized. In onesterilization technique, the instrument is placed in a closed and sealedcontainer, such as a plastic or TYVEK bag. The container and instrumentare then placed in a field of radiation that can penetrate thecontainer, such as gamma radiation, x-rays, or high-energy electrons.The radiation kills bacteria on the instrument and in the container. Thesterilized instrument can then be stored in the sterile container. Thesealed container keeps the instrument sterile until it is opened in themedical facility.

In various embodiments, some components of the instrument 10 may be partof a removable, replaceable pack that may be inserted into theinstrument 10 after the instrument 10 has been sterilized. For example,with reference to FIG. 9, in various embodiments, the battery pack 106,the controller 108, and the radio module 110 may be part of a removable,replaceable pack 140 that may be inserted into the handle 6 of theinstrument 10 after the instrument has been sterilized. For example, theremovable, replaceable pack 140 may be transferred aseptically to theinstrument 10 after the instrument has been sterilized. In such anembodiment, the pack 140 may have appropriate external connectors forconnecting to the motor 104, the switching circuit 101, the inputs 120,122, and output devices 124, etc. In such an embodiment, therefore, thepack 140 can be reused in multiple instruments 10. The cartridge 34 maybe disposed of after each use.

The above embodiments were described in the context of linear endocutterdevices with a staple cartridge. It should be noted that the tissuethickness module 60 and corresponding control circuit 100 may be used inany surgical instrument having an end effector used to clamp tissuewhere thickness of the clamped tissue is an important consideration inthe procedure. For example, the tissue thickness module 60 andcorresponding control circuit 100 may be used in circular endocutters orother types of cutting/fastening devices, such as laparoscopic devices.Also, the tissue thickness module 60 and corresponding control circuit100 does not need to be used in a device using staples to fasten thesevered tissue, but could also be used in instruments using other meansto fasten the severed tissue, as noted above. Also, the tissue thicknessmodule 60 and corresponding control circuit 100 do not need to be usedin instruments having a motor. In such embodiments, the instrument 10may employ a mechanical lockout to prevent firing. One such lockoutmechanism is described in published U.S. Patent Application PublicationNo. 2006/0025811, now U.S. Pat. No. 7,857,183, which is incorporatedherein by reference in its entirety.

In various embodiments, therefore, the present invention is directed toa surgical instrument 10 that comprises a tissue-clamping end effector12. In various embodiments, the end effector 12 comprises a moveableworking instrument (e.g., a cutting instrument) 34 and a tissuethickness module 60 that senses the thickness of tissue clamped in theend effector 12. The surgical instrument 10 also comprises a controlcircuit 100 in communication with the tissue thickness module, where thecontrol circuit prevents actuation of the working instrument when thethickness of the tissue clamped in the end effector is not within aspecified thickness range. According to various implementations, the endeffector comprises: first and second opposing jaw members 22, 24; and adisposable cartridge 34 (such as a disposable staple cartridge) locatedin the first jaw member 22, where the tissue thickness module is part ofthe disposable cartridge. Also, the tissue thickness module may comprisea Hall effect sensor 64, and the second jaw member comprises a magnet78, where the Hall effect sensor senses a magnetic field strength fromthe magnet that is indicative of the thickness of the tissue clamped inthe end effector when the end effector is in the closed (or clamped)position. In addition, the tissue thickness module communicates data tothe control circuit, the data comprising: (i) data indicative of thethickness of the tissue clamped in the end effector; and (ii) dataindicative of a cartridge type of the disposable cartridge.

The control circuit may comprise a processing unit 114 programmed todetermine whether the tissue clamped in the end effector is within thespecified thickness range for the disposable cartridge based on the datacommunicated to the control circuit by the tissue thickness module,including the data indicative of the thickness of the tissue clamped inthe end effector and the data indicative of the cartridge type of thedisposable cartridge. Additionally, the control circuit may comprisesolid state memory 116 that stores thickness range data for one or morecartridge types. The processing unit may be programmed to determinewhether the tissue clamped in the end effector is within the specifiedthickness range for the disposable cartridge based on the datacommunicated to the control circuit by the tissue thickness module bycomparing the data indicative of the thickness of the tissue clamped inthe end effector to stored thickness range data for the cartridge typeof the disposable cartridge in the end effector.

In addition, the surgical instrument may further comprises an electricmotor 104 that actuates the drive shaft 48, 50, and a battery pack 106that supplies electrical power to the electric motor. The controlcircuit may prevent actuation of the electric motor when the thicknessof the tissue clamped in the end effector is not within a specifiedthickness range.

Also, in various embodiments, the tissue thickness module is in wirelesscommunication with the control circuit. The tissue thickness module maycomprise a first radio module and the control circuit may comprise asecond radio module, where the first radio module wirelesslycommunicates with the second radio module. In addition, the tissuethickness module may be in communication with a remote visual displayunit or a remote computer system.

While this invention has been described as having exemplary designs, thepresent invention may be further modified within the spirit and scope ofthe disclosure. This application is therefore intended to cover anyvariations, uses, or adaptations of the invention using its generalprinciples. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains.

What is claimed is:
 1. A surgical instrument comprising: an electricmotor; a power source connected to the motor for supplying electricpower to the electric motor; a tissue-clamping end effector thatcomprises: a moveable working portion that is moveable upon actuation ofthe electric motor; a cartridge assembly that comprises a tissuethickness sensor for sensing a thickness of tissue clamped in the endeffector; and a control circuit in communication with the tissuethickness sensor, wherein the control circuit automatically preventsactuation of the moveable working portion when the thickness of thetissue clamped in the end effector is not within a specified thicknessrange based on at least: thickness data from the tissue thickness sensorfor the tissue clamped in the end effector; and model type data for thecartridge assembly.
 2. The surgical instrument of claim 1, wherein theend effector comprises first and second opposing jaw members forclamping the tissue.
 3. The surgical instrument of claim 2, wherein thetissue thickness sensor comprises a Hall effect sensor.
 4. The surgicalinstrument of claim 3, wherein the tissue thickness sensor communicatesdata to the control circuit, the data comprising: data indicative of thethickness of the tissue clamped in the end effector; and data indicativeof the model type of the cartridge assembly.
 5. The surgical instrumentof claim 4, wherein the control circuit comprises a processing unitprogrammed to determine whether the tissue clamped in the end effectoris within the specified thickness range for the cartridge assembly basedon the data communicated to the control circuit by the tissue thicknesssensor, including the data indicative of the thickness of the tissueclamped in the end effector and the data indicative of the model type ofthe cartridge assembly.
 6. The surgical instrument of claim 2, whereinthe control circuit comprises solid state memory, wherein the solidstate memory stores thickness range data for one or more model types forthe cartridge assembly.
 7. The surgical instrument of claim 6, whereinthe processing unit is programmed to determine whether the tissueclamped in the end effector is within the specified thickness range forthe cartridge assembly based on the data communicated to the controlcircuit by the tissue thickness sensor by comparing the data indicativeof the thickness of the tissue clamped in the end effector to storedthickness range data for the model type of the cartridge assembly. 8.The surgical instrument of claim 7, wherein: the surgical instrumentfurther comprises a drive shaft that drives the moveable workingportion; the electric motor actuates the drive shaft; and the powersource comprises a battery pack that supplies the electric power to theelectric motor.
 9. The surgical instrument of claim 8, wherein thetissue thickness sensor is in wireless communication with the controlcircuit.
 10. The surgical instrument of claim 9, wherein the tissuethickness sensor is in wireless communication with a visual displayunit.
 11. The surgical instrument of claim 9, wherein the tissuethickness sensor is in wireless communication with a remote computersystem.
 12. The surgical instrument of claim 9, wherein: the tissuethickness sensor comprises a first radio module; and the control circuitcomprises a second radio module, wherein the first radio modulewirelessly communicates with the second radio module.
 13. The surgicalinstrument of claim 1, wherein the moveable working portion comprises acutting instrument.
 14. A method of operation for a surgical instrument,wherein the surgical instrument comprises: an electric motor; a powersource connected to the motor for supplying electric power to theelectric motor; a tissue-clamping end effector that comprises: amoveable working portion that is moveable upon actuation of the electricmotor; a cartridge assembly that comprises a tissue thickness sensorthat senses thickness of tissue clamped in the end effector; and acontrol circuit in communication with the tissue thickness sensor, themethod comprising: clamping tissue in the end effector; sensing, by thetissue thickness sensor, a thickness of the tissue clamped in the endeffector; transmitting, by the tissue thickness sensor to the controlcircuit, data indicative of the thickness of the tissue clamped in theend effector; determining, by the control circuit, whether the thicknessof the tissue clamped in the end effector is within a specified rangebased on a model type for the cartridge assembly; and upon adetermination by the control circuit that the thickness of the tissueclamped in the end effector is not within the specified range,preventing, by the control circuit, actuation of the moveable workingportion.
 15. The method of claim 14, wherein transmitting, by the tissuethickness sensor to the control circuit, the data indicative of thethickness of the tissue clamped in the end effector comprises wirelesslytransmitting, by the tissue thickness sensor to the control circuit, thedata indicative of the thickness of the tissue clamped in the endeffector.
 16. The method of claim 14, further comprising, prior todetermining, by the control circuit, whether the thickness of the tissueclamped in the end effector is within a specified range based on themodel type for the cartridge assembly, transmitting, by the tissuethickness sensor to the control circuit, data, indicative of the modeltype of the cartridge assembly.
 17. The method of claim 16, wherein:transmitting, by the tissue thickness sensor to the control circuit, thedata indicative of the thickness of the tissue clamped in the endeffector comprises wirelessly transmitting, by the tissue thicknesssensor to the control circuit, the data indicative of the thickness ofthe tissue clamped in the end effector; and transmitting by the tissuethickness sensor to the control circuit, the data indicative of themodel type of the cartridge assembly comprises wirelessly transmitting,by the tissue thickness sensor to the control circuit, the dataindicative of the model type of the cartridge assembly.
 18. The methodof claim 14, wherein: the power source is connected to the motor via atleast one switch; and the step of preventing, upon the determination bythe control circuit that the thickness of the tissue clamped in the endeffector is not within the specified range, actuation of the moveableworking portion comprises controlling, by the control circuit, the atleast one switch that connects the power source to the electric motor.19. The method of claim 14, wherein sensing, by the tissue thicknesssensor, the thickness of the tissue clamped in the end effectorcomprises sensing, by a Hall effect sensor of the tissue thicknesssensor, the thickness of the tissue clamped in the end effector.
 20. Themethod of claim 14, wherein determining, by the control circuit, whetherthe thickness of the tissue clamped in the end effector is within thespecified range based on the model type for the cartridge assemblycomprises comparing the received data indicative of the thickness of thetissue clamped in the end effector to data stored in a memory unit ofthe control circuit indicative of the specified thickness range for themodel type of the cartridge assembly.
 21. A surgical instrumentcomprising: a tissue-clamping end effector that comprises: a moveableworking portion; and a cartridge assembly that comprises a tissuethickness sensor for sensing a thickness of tissue clamped in the endeffector; and a control circuit in communication with the tissuethickness sensor, wherein the control circuit automatically preventsactuation of the moveable working portion when the thickness of thetissue clamped in the end effector is not within a specified thicknessrange based on at least: thickness data from the tissue thickness sensorfor the tissue clamped in the end effector; and model type data for thecartridge assembly.
 22. The surgical instrument of claim 21, wherein thecontrol circuit is in wireless communication with the tissue thicknesssensor.
 23. The surgical instrument of claim 22, wherein the tissuethickness sensor wirelessly communicates data to the control circuit,the data comprising: data indicative of the thickness of the tissueclamped in the end effector; and data indicative of the model type ofthe cartridge assembly.
 24. The surgical instrument of claim 23, whereinthe tissue thickness sensor comprises a Hall effect sensor.
 25. Thesurgical instrument of claim 23, wherein the control circuit comprises aprocessing unit programmed to determine whether the tissue clamped inthe end effector is within the specified thickness range for thecartridge assembly based on the data communicated to the control circuitby the tissue thickness sensor, including the data indicative of thethickness of the tissue clamped in the end effector and the dataindicative of the model type of the cartridge assembly.
 26. The surgicalinstrument of claim 25, wherein the control circuit comprises solidstate memory, wherein the solid state memory stores thickness range datafor one or more model types for the cartridge assembly.
 27. The surgicalinstrument of claim 26, wherein the processing unit is programmed todetermine whether the tissue clamped in the end effector is within thespecified thickness range for the cartridge assembly based on the datacommunicated to the control circuit by the tissue thickness sensor bycomparing the data indicative of the thickness of the tissue clamped inthe end effector to the stored thickness range data for the model typeof the cartridge assembly.
 28. The surgical instrument of claim 27,further comprising: a drive shaft that drives the moveable workingportion; and an electric motor that actuates the drive shaft; andwherein the control circuit prevents actuation of the electric motorwhen the thickness of the tissue clamped in the end effector is notwithin the specified thickness range.
 29. The surgical instrument ofclaim 28, wherein the moveable working portion comprises a cuttinginstrument.
 30. A surgical instrument comprising: a tissue-clamping endeffector that comprises: a moveable working portion; and a cartridgeassembly that comprises a tissue thickness sensor for sensing athickness of tissue clamped in the end effector; and a control circuitin wireless communication with the tissue thickness sensor, wherein: thecontrol circuit comprises solid state memory that stores specifiedacceptable tissue thickness range data by cartridge assembly model type;the control circuit comprises a radio circuit that receives wirelesslyfrom the tissue thickness sensor data indicative of: thickness data forthe tissue clamped in the end effector; and model type data for thecartridge assembly; and the control circuit comprises a programmablecontroller that is programmed to determine whether the thickness of thetissue clamped in the end effector is within the specified acceptabletissue thickness range for the cartridge assembly model type based on atleast (i) the stored specified acceptable tissue thickness range data bycartridge assembly model type, (ii) the thickness data for the tissueclamped in the end effector from the tissue thickness sensor, and (iii)the model type data for the cartridge assembly for the tissue thicknesssensor; and upon a determination that the tissue clamped in the endeffector is not within the specified acceptable thickness range for thecartridge assembly model type, the control circuit prevents actuation ofthe moveable working portion of the end effector.
 31. The surgicalinstrument of claim 30, further comprising: a drive shaft that drivesthe moveable working portion; and an electric motor that actuates thedrive shaft; and wherein the control circuit prevents actuation of theelectric motor when the thickness of the tissue clamped in the endeffector is not within the specified accepted thickness range.
 32. Thesurgical instrument of claim 31, further comprising: an electrical powersource; and a power switch connecting the electrical power source to theelectric motor, wherein the control circuit controls the power switchsuch that the power switch is in a non-conducting state when the controlcircuit determines that the thickness of the tissue clamped in the endeffector is within the specified acceptable thickness range for thecartridge assembly model type.
 33. The surgical instrument of claim 31,wherein the moveable working portion comprises a cutting instrument. 34.The surgical instrument of claim 33, further comprising: a firingtrigger; a firing trigger sensor for sensing actuation of the firingtrigger by an operator of the surgical instrument, wherein the firingtrigger sensor is in communication with the control circuit; and acutting instrument position sensor for sensing a position of the cuttinginstrument in the end effector, wherein the cutting instrument positionsensor is in communication with the control circuit.